Preventing Subintimal Hematoma Formation during Stingray-mediated Reentry in Chronic Total Occlusion Interventions

Background
The Stingray system (Boston Scientific, Marlborough, MA) is vital for achieving controlled reentry following subintimal antegrade dissection during coronary chronic total occlusion crossing. However, reentry can be hampered by the development of subintimal hematoma (SIH) compressing the true lumen. To mitigate that, we have routinely used a technique that allows aspiration through the Stingray wire lumen before and while advancing the reentry wire and we sought to test it in vitro.

Methods
The Stingray aspiration technique involves attaching a Copilot hemostatic valve (Abbott Vascular, Santa Clara, CA) to the wire port of the Stingray, which is then used both to introduce the reentry wire and connect an aspiration syringe (Figure 1). We used a closed, water-filled system with a silastic tube simulating the subintimal space (SIS) and measured pressures under multiple conditions.

Results
Insertion of a 0.014” wire into the Stingray results in a significant pressure rise in the SIS (peak 329±31 mmHg). Aspiration during wire introduction using our system markedly reduced the pressure rise to 126±28 mmHg (P<0.05). Aspiration from the wire port with the wire all the way in still resulted in a pressure drop confirming that sufficient space remains inside the wire lumen. This was best achieved with 10- and 20-mL syringes (dp/dt -6.3±1.4 mmHg/s) as smaller syringes did not provide adequate suction.

Conclusions
Wire introduction into the Stingray has a pistoning effect that may cause SIS expansion. Using the hemostatic valve to allow aspiration from the wire lumen before, during and after wire introduction can mitigate this effect and potentially control the SIH.